November 27 – In an interview with the German magazine Bunte, Hillary Clinton states that she will not be a candidate for the presidency in 2004, and when told that some were disappointed with that decision, replies "I know. Well, perhaps I'll do it next time around." This is interpreted to mean that she will consider a run in the 2008 race, if the 2004 Democratic nominee is unsuccessful.[2]

November 9 – Following John Kerry's loss in the 2004 election, Cameron Kerry, John Kerry's brother and political confidante states in regards to another presidential run "That's conceivable... I don't know why that [last week's loss] should necessarily be it. I think it's too early to assess. But I think that he is going to continue to fight on for the values, ideals, and issues this campaign is about."[4]

October 22 – Despite having stated that "I can unequivocally say I will not be running for national office in four years",[12] Senator Barack Obama of Illinois states in relation to a presidential run "I don't want to be coy about this: given the responses that I've been getting over the last several months, I have thought about the possibility, but I have not thought about it with the seriousness and depth that I think is required ... After November 7, I'll sit down and consider, and if at some point I change my mind, I will make a public announcement and everybody will be able to go at me."[13]

December 3 – Democratic Senator Hillary Clinton begins discussions with New York Democratic officials to indicate the possibility of a 2008 presidential campaign and to ask for their support if she does.[26]

December 4 – Republican Senator Sam Brownback of Kansas announces the formation of an exploratory committee.[27]

January 1 – Republican candidate Rudy Giuliani's campaign strategy is made public in the New York City Daily News.[35] Giuliani claims the material was stolen while the News claims it was left in a hotel accidentally.[36]

January 20 – Democratic Senator Hillary Clinton announces that she is forming an exploratory committee.[46] Republican Senator Sam Brownback of Kansas officially announces his candidacy for the 2008 Republican presidential nomination in a rally in his home state.[47]

September 21 – The Mackinac Republican Leadership Conference is held at the Grand Hotel in Mackinac Island, Michigan, featuring the traditional straw poll, which is won by Mitt Romney with 39 percent of the vote.[107]

December 16 – Republican candidate Ron Paul raises more than $6 million through online donations in 24 hours, breaking his own record of $4.3 million to become the highest figure ever raised in a day.[139]

August 24 – The Democratic National Committee unanimously votes that the delegates to the Democratic National Convention from Florida and Michigan will be fully seated. It had previously stripped both states of their delegates as punishment for moving their primary dates before February 5.[265]

September 10 – Former Republican candidate Ron Paul expresses support for Constitution Party nominee Chuck Baldwin, Green Party nominee Cynthia McKinney and independent candidate Ralph Nader in a joint press conference at the National Press Club.[272] The purpose was to outline shared principles of all: non-interventionism, civil liberties, balanced budgets, and uncorrupt monetary policy.[272]Libertarian Party nominee Bob Barr, who was invited by Paul, held a separate conference down the hall, joining in the support of shared principles, but protesting that Paul ought to endorse the Libertarian nominee (Barr himself) specifically. Barr's protest was cited[272] as a reason for not giving him the endorsement; two weeks later, Paul would instead specifically endorse[273] the Constitution Party nominee.

January 8 – Vice President Dick Cheney, in his role as President of the U.S. Senate, opens the certificates of the electoral votes from the various states, which are then counted by two tellers from the House of Representatives and two from the Senate. Cheney then announces the votes for President and Vice President.[295] Unlike previous electoral vote counts, there were no faithless electors, leaving the final tally unchanged from election day projections.